Refrigerated (reefer) trucks and trailers are typically cooled by a separate refrigeration or reefer unit, such as a diesel reefer unit. In one example, the reefer unit includes a diesel engine that powers a compressor to cool the trailer. These reefer units are typically operating continuously or at various intervals depending on conditions to maintain certain temperature conditions in the trailer.
Reefer units include various loads in addition to the compressor/evaporator. Examples include loads like fans, resistive heaters, lights and a mixture of single phase and three phase loads. In addition, various compressor technologies for the reefer unit are possible, including reciprocating type and scroll type compressors. The most significant part of the load is typically the compressor/evaporator of the reefer unit.
Current and possible future regulations for emission and noise levels, as well as fuel savings benefits, make utilization of regenerative capacity in powering reefer units more attractive. Therefore, integrated approaches for reefer units that provide flexibility and efficiency are needed.